Infrared Temperature Measurement FAQs

SENTEST handheld infrared thermometers are divided into the NP10 and NP15 series. The NP10 series has a measuring range of –30°C to 600°C, with a wavelength of 8–14 μm. It can be used for a wide variety of temperature measurement applications, such as plastics, fabrics, chemical industry, electrical equipment inspection, industrial measurement, HVAC systems, and packaging. The NP15 series is SENTEST’s high-end model. It offers a wide measuring range up to 1600°C, and comes with optional CF lens for close-range 1 mm spot measurement and FF lens for long-distance measurement. In addition to the common 8–14 μm wavelength models, SENTEST also provides rare short-wavelength handheld infrared thermometers: 1 μm (H1), 1.6 μm (H2), and 2.3 μm (H3). Among them, the NP15 H3 (100°C–600°C) is most often used for measuring temperatures of metal molds, heating rollers, and other shiny metallic surfaces.

The infrared measuring distance is theoretically unlimited. However, at longer measuring distances, many uncertain interference factors can affect accuracy. We recommend referring to our provided optical path diagram, where you can use the D:S ratio to calculate the measurement distance and the corresponding spot size (the target object must be larger than the measurement spot area).

You can contact our professional infrared temperature measurement team at service@sentest.com.

When using an infrared thermometer for measurement, you need to understand the following points: It can only measure surface temperature, not internal temperature. The target object must be larger than the measurement spot size. Material of the target: for example, shiny or polished metal surfaces measured with 8–14 μm wavelength models will cause inaccurate results. Environmental conditions: steam, dust, smoke, or corrosive liquids that block or cover the lens will affect accuracy and may even damage the instrument. Installation location: if the instrument is near equipment that generates strong magnetic fields or currents, measurement accuracy will be affected. Ambient temperature: if the environment is too hot or too cold, the instrument’s accuracy may be influenced. Please refer to the optimal operating temperature specifications of each model. Measuring through glass: short‑wavelength series products can measure through glass, but long‑wavelength 8–14 μm models cannot. Different materials require adjustment of emissivity settings.

The laser beam only serves as an aiming function; the actual temperature signal is not received through the laser. SENTEST products are available with single‑point laser (coaxial laser) and dual‑laser aiming. The dual‑laser aiming can simulate the measurement path shown in the optical diagram.

SENTEST handheld infrared thermometer (NP15H3) and fixed infrared thermometers (NS10PH3, NS50H3, NS50PH3) are all suitable for measuring the temperature of shiny metallic surfaces such as metal molds and heating rollers. These models use the 2.3 μm (H3) wavelength.

SENTEST infrared temperature measurement products support both analog and digital signal outputs. Analog outputs: 0–5 V, 4–20 mA, Type K/J Digital outputs: TTL or RS485 Modbus RTU

Fast response speed Suitable for objects that cannot be directly touched, or for hazardous and hard‑to‑reach areas No consumable costs

Textiles Infrared thermometers can measure the surface temperature of textiles, allowing more precise control during drying and shaping processes, improving production yield and maintaining quality. Metal processing / Metal surface measurement The H1, H2, and H3 series are designed for applications such as metal molds, high‑frequency heating, soldering tips, furnace walls, motors, and shafts, enabling accurate temperature measurement in high‑temperature and harsh environments. Paper and printing In papermaking, temperature control during the drying process is critical. Infrared thermometers can monitor the temperature of moving paper sheets. In printing, they can check whether the hot‑air devices used for drying ink or coatings meet required standards. Asphalt (bitumen) When installed on road rollers, infrared thermometers can monitor temperature changes of asphalt in real time during road construction. If the temperature is too high or too low, it may cause problems such as insufficient density, porosity, or uneven surfaces. Plastics Infrared thermometers can be used to monitor raw materials, product processing, extrusion, and thermoforming temperatures to ensure quality. Electrical equipment inspection Infrared thermometers can be used to check live electrical equipment, helping to detect and prevent overheating or faults that could lead to hazards. Ceramics Temperature control is critical in ceramic production (e.g., dental prosthetics). Infrared thermometers allow non‑contact, real‑time monitoring to prevent defects.

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